1. Field of the Invention
The present invention relates to an image forming apparatus and a control method thereof, and more particularly, to an image forming apparatus which enables an improvement in the efficient execution of jobs by appropriate and dynamic distribution of resources, such as memories or disks, when there is performed a concurrent operation in which a plurality of types of jobs are executed concurrently, as well as to a control method thereof.
2. Description of the Related Art
When installed in an office or the like, a multi-function machine (hereinafter abbreviated to an xe2x80x9cMF machinexe2x80x9d) which fulfils a plurality of functions, such as a copy function, a scanner function, a printer function, and a facsimile function, is usually shared among a plurality of users. In such a case, a certain user uses the MF machine as a network printer, and another user uses the MF machine as a copier. Requests for offer of various functions (i.e., job requests) from a plurality of users may simultaneously concentrate on such an MF machine shared among a plurality of users. Under such a condition, a conventional image forming apparatus having multiple functions has employed a method of time-sequentially processing a plurality of job requests.
The job concentration is attributable to contention for shared resources within the imaging forming apparatus which are required for executing a plurality of job requests that arise simultaneously. The shared resources include image reading means (hereinafter referred to as an xe2x80x9cimage input terminalxe2x80x9d or xe2x80x9cIITxe2x80x9d), image output means (hereinafter referred to as an xe2x80x9cimage output terminalxe2x80x9d or xe2x80x9cIOTxe2x80x9d), memory, secondary storage means such as a hard disk, a document feeder, a sorter, a finisher, and the like.
Under the method by which a plurality of job requests are processed time-sequentially, a plurality of users cannot utilize the functions of the MF machine at one time. For this reason, when a specific job is being executed, another job must wait for execution. In such a case, an urgent network print job requested by a certain user, for example, may wait until there is executed another not-so-urgent job, such as receipt of a facsimile transmittal or a direct mail or a print job.
To solve such a problem, a digital copier system disclosed in, e.g., Japanese Patent Unexamined Publication No. Hei. 6-350772, is configured in such a way as to determine the sequence of use of shared resources according to a predetermined order of precedence, to enable a user to set the order of precedence according to the types of jobs, or to concurrently process a plurality of jobs by allowing alternative use of shared resources, in a case where a plurality of types of job request arise simultaneously. By employment of such a processing scheme, the user prioritizes a plurality of job requests by assigning a high priority to an urgent job request beforehand or by imparting the right to use the shared resources alternately to the jobs assigned the same priority, thereby greatly improving the operability of the digital copier system.
In the digital copier system disclosed in Japanese Patent Unexamined Publication No. Hei. 6-350772, since the order in which jobs are executed is defined according to the preset sequence of preference, lower priority jobs are eventually brought into a wait state. For example, since a job of printing only one page is of lower priority, the job may be brought into a wait state for a long period of time until completion of a higher priority job having a necessity of printing a document of fifty pages, such as receipt of a facsimile transmittal or a print job.

An object of the present invention is to provide an image forming apparatus which can provide improved operability to individual users by appropriately distributing resources even when a plurality of job requests arise simultaneously, as well as to provide a control method thereof.
To achieve the above object, according to a first aspect of the present invention, there is provided an image forming apparatus for concurrently executing a plurality of types of jobs through use of shared resources, the apparatus comprising: job control means for controlling execution of a job; and resource management means for managing a state of use of the shared resources and allocating the shared resources required for executing the job in response to a request from the job control means when the job control means executes the job.
According to a second aspect of the present invention, there is provided an image forming apparatus for concurrently executing a plurality of types of jobs, the apparatus comprising: job priority determination means for determining priorities of the jobs.
According to a third aspect of the present invention, there is provided a method of controlling an image forming apparatus for concurrently executing a plurality of types of jobs through use of shared resources, wherein shared resources required for executing a job are allocated at the time of execution of the job by management of state of use of the shared resources.